<!DOCTYPE html>
<html>
<head>
<style>

.button {
  background-color: #4CAF50; /* 绿色 */
  border: none;
  color: white;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  margin: 4px 2px;
  cursor: pointer;
}

.button2 {background-color: #008CBA;} /* 蓝色 */
.button3 {background-color: #f44336;} /* 黑色 */ 
.button4 {background-color: #e7e7e7; color: black;} /* 灰色 */ 
.button5 {background-color: #555555;} /* 黑色 */
</style>
</head>
<body>

<h1>按钮颜色</h1>

<p>通过 background-color 属性改变按钮的背景色：</p>

<button class="button">绿色</button>
<button class="button button2">蓝色</button>
<button class="button button3">红色</button>
<button class="button button4">灰色</button>
<button class="button button5">黑色</button>

</body>
</html>
